Process and apparatus for production of fiber from vegetable matter



Aug. 6, 1946. c. c. HERITAGE v 2,405,213

PROCESS AND APPARATUS FOR PRODUCTION OF VFIBER FROM VEGETABLE MATTERFiled Aug. s, '1940 space by the expansion of v content of the originalPatente ug. 6, ld

PBOGESS AND APP l,

TON F MTTER 'ros non Pnonuc- .'le snor/r vnoa'rnnnn Clark C. Heritage,Cloduet, Minn., asslor to Wood Conversion Coni corporation oi Belawarpany, Cloquet, e

Application August 3, 1940, Serial No. 351,066

(ci. az-o) Cla.

The present invention relates generally to the production of pulp, andin particular to apparatus therefor. p Reference is made to the AsplundU. S. Patent No. 2,008,892, describing a machine for the production ofpulp. The raw material in the form of wood chips, grasses, straw,bagasse, cane, and the like is fed into a. magazine ahead of a steampressure chamber in which is housed a rotary device for reducing thematerial to pulp in a steam environment and particularly in the absenceof suspending water. Beyond the defibering chamber there is an outletdevice having in series alternately operating valved orice's. By thisdevice, one oriiice discharges from the machine while the other oriiiceis closed. The :fiber trapped be-` tween the valves is discharged fromthe intervalve the high temperature steam also trapped in said space. Asoriginally taught and disclosed the said device discharges the ber intowater.

In applying the Asplund machine to other uses. wherein it becamedesirable to dry the ber directly, the discharged fiber was carried by abelttype conveyer. to a suitable drier device which happened to belocated at some distance from the machine and at a. considerable heightabove it.

One object of the present invention is to provide means to carry thedischarged fiber from the machine for considerable distances away fromand even to a higher level, without the use .of mechanical means andpower to convey the fiber.

In particular, it is an object of the invention to utilize the pressureof the discharged steam to convey the ber for long distances with orwithout elevation.

n is sun a further object of the invention to provide a cyclone systemat the end of said conduit for separating :dber and any steam or gasesattendant the discharged material.

A further object of the invention is to provide to said cyclone system asupply of drying gas or air for the removal of water from, or fordrying, the ber in the cyclone system.

It is also an object oi the invention continuously to reducelignocellulose raw material, especially wood, to a mass of ilbers, andespecially dry fibers, with retention of substantially all the solidmaterial, and with change in the content of the original material sothat it presents less resistance to certain treatments by ,water.chemical solutions` and other reagents, where it is desired to use theber as a starting point to produce bers lacking in some of the solidcontent of the original wood other than its alpha cellulose content.

Various other and ancillary objects and advantages of-the invention willbecome apparent from the following description and explanation of theinvention, as illustrated by the accompanying drawing in which:

2 that a back I many factors involved Fig. 1 represents a plan view of amachine according to the Asplund U. S. Patents No. 2,008,892 and No.2,145,851.

Fig. 2 represents a. conduit and a cyclone system attachedy to themachine and used to separate steam and gas from the rlber as formed, andused also to dry the ilber.

The apparatus not only provides economy in power and convenience inhandling, but may give desirable processing to the ber. It is a statedobjective of the Asplund patent and its process Patent No. 2,008,892, tominimize the time of exposure of the material to the elevatedtemperatures used in forming the liber. yIn connection with otherdevelopments employing forming conditions as they emst in the saidAsplund machine, I have found that it may be desirable to expose thematerial, and especially the formed ilber, to elevated temperatures, andparticularly to steam, ior a much longer time than is permitted bynormal operation of said machine. l

By employing a long conduit, I have discovered pressure may existcontinuously in the conduit at the discharging orifice of the machine.This is reduced as the body of ber carriecl in the conduit moves ontoward the discharge end into the atmosphere or other receiving space-of pressure lower than that in the debering machine. Of course, thelength of this pressure zone in the conduit is dependent in part uponradiation from the conduit, which may be controlled by insulation or itsheat surroundings, or both. ere the gas pressure ceases to exist in theconduit the fiber is moved along as a column :by mechanical pressurefrom that portion of the ber which is moved bythe gas pressure.

It is vof course to be understood that there are which anyone skilled inthe art will naturally be obliged to consider in in,- stalling oroperating the apparatus.- Friction of fiber with the conduit, weight ofthe' column of iiber tobe lifted, and the existing moisture of addedcondensate, are all forces opposing the pressure. With these oppositionforces also must be considered the loss or pressure in the gas or steamas a result of its expansion or its cooling.

However, in spite of all these oppositions, I have found that a conduitin diameter the same as the machine oriiice, say 6 inches, may extendior 150 to 200 feet and at the same time elevate the :ber

. by as much as 50 feet, the conduit discharging may be operated to intoair from a deiibering pressure of lbs. per sq. in. steam pressure. Suchdistances readily accommodate various pieces of equipment in a plant, atdifferent levels, and at remote locations, to simple connection by aconduit to a iixedly located debering machine, whereby a plant is madeflexible, and whereby a defiberingmachine produce and discharge fiberfor various processes of utilization.

The exposure of raw material to thesteam'in the machine continues forsuch a short time, that the chemical reaction-in the machine is limited.I have found for example, that by extracting bers ofraw aspen not at al1preheated, using 2% ber consistency in water for two hours, the watersoluble extract is about 4% to 5% of the dry wood used. Using liberdebered in the Asplund machine at 135 lbs. pressure of steam;and imme-4diately exposed to the atmosphere, the watersoluble content is about Ihave also determined that prolonged exposures to steam will bringthelike water extract to about 2'1 as a practical limit. By use of theconduit as a steam chamber I may control water solubles to variousdegrees, in the case of aspen, between substantially 10% and 27%. I havealso found that high temperatures and short times can produce as muchwater-extract as a certain combination of lower temperature and longertime, there being less darkening of the ber at the latter condition.Hence, for prolonging the steam eilect it is desirable to use alowertemperature than exists in I the Asplund machine. The dischargingvalve structure of the Asplund machine-is an excellent pressure reducingdevice for such purpose, and the lengthy conduit is an excellent meansfor prolonging the time of exposure.

esdry m Fig. 1, an spinne machine is illustrated in' part, showing theessential parts.

A tubular chamber i 0 is used to introduce wood as chips, or otherlignocellulose material into a high pressure environment within themachine. The inlet i0 has a serrated or notched interior wall which actsto prevent steam pressure Vpushing back a plug in the inlet iormed'ofthe raw material by the action of a ram or plunger I I, acting on rawmaterial fed into the path of the plunger through a hopper opening i2(Fig. l) under a hopper i3 (Fig. 2). The inlet l0 opens into a magazineil capable of holding high pressure steam therein. The bottom of themagazine connects by a passageway i5 having a screw conveyer I6 therein,operated on the axis i1, by power.

connection i8. The conveyor feeds the raw material to the center ofopposed grinding disks 2d and 2|. Disk 20 is stationary and receives theraw material near its center. Disk 2| rotates at high speed onconnection 23. Means (not shown) permits adjusting the spacing betweenthe disks. A housing 24 for the grinding disks opens .to an outletconnection 25. Steam is fed from a supply 26 to a distributing system 21for introducing the steam into various inlets to the spaces within themachine.

The outlet is connected to an oflset extenthus led into a fan housingaxle 22, driven by a powerful belt Y sion xture 28 with valves 30 and 3lat its ends.

The valves are arranged to have parallel operat 33. and mechanism (notshown) so operates them that when one is closed or substantially so theotheris open or substantially so, as indicated by stressed arrows 34 and24". These reciprocate rapidly andin operation, rst admit steamandberintothexture ,thenatleast ingstemsSZand partially closetheAiixture at the machine end other end to discharge the opening of thevalves and control the the ilber while opening at the ber. The degree ofthe vtiming is adjustable, in order to amount or steam pressureaccompanying to move it along as described below.

The discharge end or nx'ture 2l is connected by elbow 35 to an extendingconduit 3i, shown in Fig. 2 only in cross-section, indicating itsvertical extent, better shown in Fig.

longV distances' horizontally and vertically, and

2. IThis may run for' be branched and valve-controlled. To avoidplugging bythe body of ber moving therein, sharp angles are avoided, asrepresented by sweeping bends and Il. A Y fixture l2 and valves 43 andIl are shown, as oi the gate type. These may be opened readily, but forclosing, the supply of fiber may be stopped until the valve is clearedby the end of the moving liber. Branch I5 leading from valve 43represents a supply to any use. Branch IB leading from valve 44represents connection to a cyclone or cyclone system.

In the machine, some slight amount oi' gas ls generated from reactionsin the wood at the temperature of the steam, and it is desirable todischarge these. This is permitted by any 'simple cyclone to separatethe fiber from the gas and also any residual steam, the discharged berbeing moist. Where moist liber is useful, it may be taken from such asimple cyclone. However, for the purpose of producing dry fiber, thefirst cyclone is made a part of a cyclone drying system as nowdescribed.

A plurality of cyclones is used, the number being dependent upon designto effect ultimately a fiber. Four are illustrated and designated 50,5l, 52 and 53. Conduit 46 enters the top of cyclone 50 which dischargesgas and steam to the atmosphere at 54. The bottom of cyclone 50 hasalternative outlets, merely for the purpose .of illustration. Outlet 55represents the path for removing moist fiber, and a valve 56 is shown tocut on such outlet. The other outlet is associated with the cyclonesystem as follows:

Cyclone 50 drops the iiber into a housing 51 in which a vaned rotor 58operated by motor 59, drops the fiber into a conduit S0 supplied by hotgas from a supply main 6l Fiber and hot air are 63 which blows itthrough conduit 54 into cyclone 5 i The cyclones 5I and 52 continue theseries in the same way by like equipment, with some lows: hot gasconduits 55 and 66, fans S1 and 68. ian-outlet conduits 69 and T0.Conduit 10 leads into cyclone 53, which drops dry ilber into e, receiver1i.

Where the fiber is useful dry, a high yield is obtained from Wood or thelike with substantially all the solid substance preserved, as describedin my copending application U. S. Serial No. 227,338, now abandoned,filed August 29, 1938, of which the present invention is a continuationin part.

Where the ber is to be used as a raw material for a solvent extraction,the moist or the dry fiber may be used for extraction by an aqueoussolvent.

The extent to which the liber is subjected to steam (see my copendingapplication U. S. Serial Nos. 351,041 to 351,065, filed August 3, 1940,and related cases), inuences the content of extractable-matter and thecharacter of the liber.

composition.y By design and operation as above described, the extent oftime and exposure to parts indicated as folv debering means in to feedlignocellu-` -movement of the said nbermg by said centering means, saidfeeding means being arranged and constructed to prevent the exit ofsteam from said chamber, pressurereducing means operated to openintermittently in rapid succession for providing an outlet from saidchamber for steam and ber, whereby small .batches of loose ber aredischarged in rapid whereby said pressure-reducing means freelydischarges ber in to saidconduit and into an atmosphere of steam under apressure which eects small batches of ber along the conduit to saiddischarge end While exposing all the bers thereof to the steam in saidconduit for a period of time during traverse of the conduit, the lengthof said conduit further being such that the time of exposure of bers inAsaid conduit to steam is longer than the time of exposure oflignocellulose to steam in said chamber.

2. Apparatus for continuously producing ber comprising in combination ahigh pressure chamber for containing steam under pressure, means to feedhigh pressure steam into said chamber at a temperature to effectsoftening of lignocellulose said chamber, whereby thermal action in theand at which the lignocellulose becomes softened continuouslydischarging steam and ber froml said chamber into an elongated laterallyconned space and reducing the pressure of the steam at said discharge,while continuously moving said ber alongsaid space and discharging saidber from said space by the reduced pressure o1' said steam into a regionof pressure still lower than said reduced pressure, and while employingthe length of said space to create a pressure of steam increasing in thedirection from said region to presence of steam is'eiected on all theber in said space to alter its composition as it moves alongsaidelongated space..

4. The method of continuously producing ber which comprises continuouslyintroducing lignoceilulose material t be defibered into a pressuredebering said lignocelluchamber an'd in the absence of a suspendingquantity of water at a temperature above 212 F.

to permit ready debration, while substantially continuously dischargingsteam and ber from said chamber into an elongated laterally' connedspace and reducing the pressure of the steam at said discharge whilecontinuously moving said length of said space .to create in saidchamber, feeding means to feed lignocellu- 1,

lose vegetable matter into said chamber to be debered, said feedingmeans being arranged andv constructed to prevent the exit of steam fromsaid' chamber, rotary debering means in said charnber, means within saidchamber to feed said lignocellulose to said debering means,pressure-reducing means operated to open intermittently in rapidsuccession for providing an outlet from said chamber for steam and ber,whereby small batches of loose ber are discharged in rapid succession,and an open-ended conduit connected to and extending from saidpressure-reducing mean for containing ber and steam under pressure-andfor conveying the ber, said conduit l having a length and cross-sectionwhich together are such as to permit said pressure-reducing means toeiect a reduction in pressure and t0 `cause a back pressure of steam insaid conduit increasing from the open and discharge, end of said conduitto said outlet of said chamber,

whereby said pressure-reducing means freely discharges ber into saidconduit and into an atmosphere of steam under a pressure which effectsmovement of the said small batches of ber along the conduit to saiddischarge endwhile exposing all the bers thereof to the steam in saidconduit for a period of time during traverse of the conduit, the lengthof said conduit further being such that the time of exposure of bers insaid conduit to steam is longer than the time of exposure oflignocellulose to steam in said chamber.

. 3. The method of continuously producingber which comprisescontinuously introducing lignocellulose material to be debered into apressure chamber, continuously debering said lignocellulose mechanicallyin the presence of steam in said chamber and in the absence of asuspending quantity of water at a temperature above 212 F. and at whichthe lignocellulose becomes softened to permit ready debration. whilesubstantially ber along said space and discharging said ber from saidspace by the reduced pressure of said steam into a rgion of pressuresti1l.lower than said reduced pressure, and vvhile employing the `apressure of steam increasing in the direction from said region to saidchamber, whereby thermal action in the presence of steam is effected onall the ber in said space to alter its composition as it moves alongsaid elongated space, the time of exposure of the ber to steam at thereduced pressure in said space being longer than the time of exposure ofthe lignocellulose to steam at the higher pressure in said chamber.

5. The method of continuously producing ber which comprises continuouslyintroducing lignocellulose material to be deflbered into a pressurechamber, continuously debering said lignocellulose mechanically in thepresence of steam in said chamber and in the absence of a suspendingquantity of water at a temperature above 212 F. and at which thelignocellulose becomes softened to permit ready debration, whilesubstantially continuously discharging said chamber into an elongatedlaterally conned space and reducing the pressure of the steam at saiddischarge, while continuously moving said ber along said space anddischarging said-ber from said space by the reduced pressure of saidsteam into a region of pressure still lower than said` reduced pressure,and while employing the length of said space to create a pressure ofsteam increasing inthe direction frdm said region to said chamber,whereby thermal action in the sure in said chamber.

,CLARK C. HERITAGE steam and ber from

